Fuel cock should be on, but currently the whole multiplayer stuff is so unstable (at least in my PC), that I think I'll wait for the next patch before continuing CEM experimenting. I get freezes almost every time.
Not sure of your PC equipment, but I would suggest trying either turning off shadows, turn the textures to medium and turn trees to off, you may not need to do the first two depending on your set up, but the trees off is apparently helping with the online sound loss issue, also SSAO off and no epileptic filter, unless you feel you need it on that is.